Shiraz UniversityIranian Journal of Materials Forming2383-00428220210401Iranian Journal of Materials Forming, Issue 2, April 202123608210.22099/ijmf.2021.40228.1180ENRaminEbrahimiDepartment of Materials Science and Engineering, School of Engineering, Shiraz University, Iran.0000-0001-8057-5733Journal Article20210404The “Iranian Journal of Materials Forming (IJMF)” is an international open access journal in the fields of materials deformation and forming processes, which was established at Shiraz University in 2014. The journal is pleased to receive papers from scientists and engineers from academic and industrial areas related to all manufacturing processes. In addition, all deformations, including the elastic and plastic behaviors of materials and deformations due to failure are part of this journal's field of interest. This journal has been a quarterly issue and from 2021 onwards, it will at least publish 24 articles a year with the aim of having a quantitative criterion for entering Scopus. The quality and credibility of the journal has been ensured by appointing some of the most well-known professors in the world as members of its editorial board. Recently, some world-renowned scientists have also been added to the editorial board making it stronger than before.https://ijmf.shirazu.ac.ir/article_6082_37a35010863bb3625ad6f4d2eb40f257.pdfShiraz UniversityIranian Journal of Materials Forming2383-00428220210401Microstructure Evolution of the Stainless Steel 316L Subjected to Different Routes of Equal Channel Angular Pressing411607510.22099/ijmf.2021.38714.1169ENMojtabaAskari Khan-abadiDepartment of Materials Science and Metallurgical Engineering, Ferdowsi University of Mashhad, Azadi Square, Mashhad, IranMohammad HassanFarshidiDepartment of Materials Science and Metallurgical Engineering, Ferdowsi University of Mashhad, Azadi Square, Mashhad, IranMohammad HadiMoayedDepartment of Materials Science and Metallurgical Engineering, Ferdowsi University of Mashhad, Azadi Square, Mashhad, IranJournal Article20201012During the past decades, equal channel angular pressing has risen as a promising severe plastic deformation process and it is applied for the grain refinement and strengthening of metallic materials. Although the application of this process to improve the characteristics of austenitic stainless steels has been studied to some extent, little studies have considered the effect of route of the ECAP on this matter. This study aims to study the evolution of microstructure and the increase of hardness of stainless steel 316L during processing by two different routes of this process. For this purpose, the alloy is processed at the deformation temperature of 310 °C using two different routes of A and B<sub>c</sub>. Afterwards, the microstructure evolution of the alloy is studied using the X-ray diffraction and the scanning electron microscopy. Results show that the applied ECAP procedure, irrespective of the applied route, causes a negligible occurrence of the phase transformation while it causes a widespread occurrence of twinning. This fact is related to the elevated temperature applied for the process. Also, the process causes a considerable increase in the hardness of the alloy mainly attributed to the occurrence of twinning.https://ijmf.shirazu.ac.ir/article_6075_fa7e4a0b0b9768518a0b33c744ec439b.pdfShiraz UniversityIranian Journal of Materials Forming2383-00428220210401Effect of Fabrication Method and Porosity Content on Elastic Modulus of a Nano-Particle Dispersed Nickel Base Alloy1221607610.22099/ijmf.2021.37820.1160ENMohammad JafarHadianfardDepartment of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz, IranRezaKavosi HeydarDepartment of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz, IranSeyed MohammadArabDepartment of Mechanical Engineering, University of Mohaghegh Ardabili, Ardabil, IranJournal Article20200711The change in the elastic modulus of mechanically alloyed MA754 Ni-based superalloy as a function of the porosity and fabricating method has been discussed in this study. A mixed powder of a nano-particle strengthened nickel alloy was prepared directly from its alloying elements via mechanical alloying. The mixture then consolidated using two different powder metallurgy methods, pressing was followed by sintering and as was hot extrusion followed by drawing. The powder and solid parts were characterized by XRD, XRF, and microscopic examination. The porosity content and the elastic modulus of the samples were measured via Archimedes, image analysis, tensile, and/or compression tests, respectively. The results indicated that two methods of porosity measurement provided different values for each specimen. In addition, results showed, while processing method has influences on porosity content, it also affects the elastic modulus of the alloy tremendously. Two different values of experimental modulus can be justified by the effect of texture. The different linear and polynomial models are given for different methods of the processing.https://ijmf.shirazu.ac.ir/article_6076_2e1819e0cf104a2835544d7206d90b1c.pdfShiraz UniversityIranian Journal of Materials Forming2383-00428220210401Investigation of Stress Concentration Factors for Functionally Graded Hollow Tubes with Curved Edges under Torsion2234607810.22099/ijmf.2021.39443.1175ENZohrehEbrahimiMechanical Engineering Department, Payame Noor University, Iran.0000-0002-8460-9803SamanehNegahbanMechanical Engineering Department, Payame Noor University, IranJournal Article20210108In this paper, a finite element (FE) model is developed to calculate stress concentration factors of functionally graded (FG) hollow tubes under torsion. First, the shear stresses in FG hollow tubes with curved edges are investigated for different curvature radius of the cross-section corners. Next, stress concentrations are evaluated at low curvature parts of the cross-sections. Due to stress concentrations in low curvature regions, more considerable shear stresses are obtained. FE results are compared with the results of an analytical method for analysis of the torsion of hollow tubes to verify the computational approaches. Except for the points of stress concentrations, in other regions, an excellent agreement is found between analytical and FE results. Therefore, in stress concentration regions, regarding the error of analytical formula in stress analysis, some correction factor is presented. These stress concentration factors are calculated for a variety of curvature radius and cross-section thicknesses. Applying the presented factors, the proposed analytical formula can be used for stress evaluations, even at stress concentration regions. Finally, the effects of changing the volume fraction of the constituent phases are investigated for a range of curvature radius of cross-section corners.https://ijmf.shirazu.ac.ir/article_6078_0db9115c3dcfa6643ffc8d808dc55324.pdfShiraz UniversityIranian Journal of Materials Forming2383-00428220210401The Experimental and Numerical Study of the Effects of Holding Force, Die Radius, Pin Radius and Pin Distance on Springback in a Stretch Bending Test3543607710.22099/ijmf.2021.39387.1172ENMiladCheraghiDepartment of Mechanical Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah, IranAliAdelkhaniDepartment of Mechanical Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran.MohammadmahdiAttarDepartment of Mechanical Engineering, Hamedan Branch, Islamic Azad University, Hamedan, IranJournal Article20210101The stretch bending test is one of the methods for forming metals, especially sheets. In this method, a piece of a metal sheet simultaneously undergoes compressive and tensile forces, thereby being converted into a curved piece with a great curvature. In the present research, springback was studied using a U-form die in a stretch bending test, and the experiments were performed on st12 steels through a laboratory set-up. Moreover, various parameters were investigated, including die radius, pin diameters, blank holding force (BHF), and distance between pins. The stretching depth was 10 mm. Not to mention, springback is affected by technical and geometric parameters. For example, the results of the present study revealed that increasing the pin spacing led to the reduction of springback and for more spacing, the springback tends to spring-go, additionally, it was observed that a rise in the die radius, pin diameters, and blank holder force resulted in the reduction of springback.https://ijmf.shirazu.ac.ir/article_6077_493c92bce85c66b8309ba2015809b064.pdfShiraz UniversityIranian Journal of Materials Forming2383-00428220210401Hot Workability and Processing Map of High Gd Content Mg-Gd-Zn-Zr-Nd Alloy4453607910.22099/ijmf.2021.39414.1173ENSaharMosadeghFaculty of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran, IranMehrdadAghaie-khafriFaculty of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran, IranBehzadBineshDepartment of Materials Science and Engineering, University of Bonab, Bonab, IranJournal Article20210104Hot workability of as-extruded high Gd content Mg-5Gd-0,5Zn-0.5Zr-2.5Nd alloy was investigated using the hot compression test in a temperature range of 300-500 °C and strain rates of 0.001-1s<sup>-1</sup>. Hot workability assessment was conducted by capturing microstructural evolution of high temperature deformed samples, and by constructing power dissipation and instability maps. Using experimental data of hot compression tests, the power dissipation map of the alloy was constructed, in which a domain of dynamic recrystallization (DRX) occurred at the temperature range of 350-450 °C and strain rate of 0.001-0.1 s<sup>-1</sup>, representing the optimum hot working window. Furthermore, the processing map of the alloy was constructed, and flow instability regions were also indicated based on the Ziegler's flow instability criterion.https://ijmf.shirazu.ac.ir/article_6079_4a9dbf30c9ad8ea1604ccf816ec12e07.pdfShiraz UniversityIranian Journal of Materials Forming2383-00428220210401Constitutive Modeling of 7075 Aluminum Alloy under the Hot Compression Condition5463608510.22099/ijmf.2021.39380.1171ENSajadRasaeeDepartment of Mechanical Engineering, Faculty of Engineering, Kermanshah University of Technology, Kermanshah, IranAmirHosseinMirzaeiDepartment of Mechanical Engineering, Faculty of Engineering, Kermanshah University of Technology, Kermanshah, IranJournal Article20210101The behavior of Al7075 during the hot compression in a wide range of temperatures, 623-773 K, and strain rates, 0.001-1 s-1, were investigated in this paper. Moreover, using the standard Arrhenius constitutive models, a mathematical equation was proposed for predicting the flow stress, and then the accuracy of the model was examined using standard verification methods. The increasing of temperature and strain rate, respectively, have a reverse and direct effect on the flow stress, which can be expressed using the Zener-Hollomon parameter with the activation energy of 304 kJ/mol. Since the potential dependence of the constants in the model has not been considered for any parameter, the accuracy of the standard model is low. It was found that the values of these constants depend on the strain, so for each of the constants, a relation was obtained in terms of strain to express this relation properly. The modified model not only precisely predicts the flow stress but also provides higher accuracy in predicting the trend of variation of stress due to the influence of metallurgical evolutions occurring during the process of hot deformation, such as dynamic recrystallization or softening and hardening.https://ijmf.shirazu.ac.ir/article_6085_edbdf041d3de1e2c7f8e2c44677da01f.pdf